The art of framing a window can often be difficult and in many cases problems arise in fitting the frame around the window. Most conventional window frames are produced on mass for cost saving purposes as opposed to individually crafted frames which are substantially more expensive.
Vinyl and other thermoplastic frames are becoming ever more popular. Each of the frame sections, i.e. jambs, header and sill are cut from extruded lineals substantially longer than the length of each individual frame section. In cases where the window pane is fixed directly within the frame, each frame section has a two piece construction with the pieces being secured to one another from opposite sides of the pane. The opposing pieces of each frame section must be cut to an identical length, otherwise, the frame cannot be assembled. Furthermore, the pieces of each frame section need to be properly aligned with one another in order to receive securing screws at specific locations typically in the form or portholes provided in the frame material. As a further problem, these portholes may be stripped by the screw in which case the screw must be removed and the porthole rebuilt in order for the screw to properly secure the frame pieces.
Some of the window frames today are made from molded frame pieces which do provide accuracy of fit but which are very expensive principally due to the initial mold set up costs. Furthermore, molded frame pieces still suffer from screw stripping problems.